This application relates to battery or power packs of the rechargeable type and, in particular to lead-acid, thin metal film battery packs. The application relates to monitoring the voltage of the storage battery of the battery pack as well as the voltage provided by an associated charger coupled to the battery pack.
It is known to provide battery packs, i.e., compact arrangements of one or more battery cells, for various DC battery power delivery applications. One such application is for use in jump-starting automotive vehicles. Such battery packs typically use lead-acid battery cells, some of which have recently been of the thin metal film type. Such thin metal film lead-acid battery cells are sold, for example, by Johnson Controls, Inc. under the designation xe2x80x9cInspiraxe2x80x9d and by Bolder Technologies under the designation xe2x80x9cBolder 9/5 Sub-C TMFxe2x80x9d (Thin Metal Film).
Prior jump-starting battery packs have been provided with LED status lights. A battery pack sold by Bolder Technologies under the designation xe2x80x9cBolder SecureStart Instant Engine Starterxe2x80x9d includes a low battery voltage alert beeper, as well as LED indicators of battery voltage level. These indicators operate automatically when the battery pack is connected to a charger and are otherwise pushbutton-activated. However, the prior units do not provide any means for determining an overvoltage charging condition, or for automatically determining whether or not the battery is properly accepting a charge. If the system is being charged it is up to the operator to periodically check the battery voltage condition and to keep track of how long the battery has been charging without reaching a fully-charged condition and, if too long, to manually disconnect the charger or take other appropriate action. Furthermore, prior systems do not tailor the charging rate to the condition of the battery.
This application discloses an improved monitoring circuit for use with jump-starting battery packs, which avoids the disadvantages of prior such circuits while affording additional structural and operating advantages.
An important aspect is the provision of a monitoring circuit for a jump-starting battery pack which is fully automatic.
In connection with the foregoing aspect, another aspect is the provision of a monitoring circuit of the type set forth, which monitors not only the battery voltage, but also the voltage at a charger input port.
Still another aspect is the provision of a monitoring circuit of the type set forth, which automatically recognizes a failed battery.
Still another aspect is the provision of a monitoring circuit of the type set forth, which will alert a user if the battery voltage is too high and will automatically adjust the charging rate in accordance with the difference between charging voltage and battery voltage.
Still another aspect is the provision of a monitoring circuit of the type set forth which is powered by the storage battery of the battery pack being monitored, without significantly loading that battery.